DATAMONGO-826 - Polished poms.

Removed Spring dependency versions and fixed repository declarations.
DATAMONGO-686 - Fixed potential race-condition in QueryMapper.

We now create a new a new DBObject in QueryMapper#getMappedValue() instead of replacing them in the original objects in order to prevent the original query object being manipulated.

Added test case to verify that the original DBObject is not manipulated.

Original pull request: #111.